1. Field of Invention
The present system applies to the field of refrigeration systems applicable to use in large supermarket store fixtures and similar constructions. More particularly such refrigeration systems frequently effect defrosting by the passage of hot refrigerant gas directly from the output of the compressors to the evaporators which desire defrost. In this manner, the defrosting evaporator will cease refrigeration for a certain period of time and hot gaseous refrigerant will be drawn from the discharge line of the compressor to pass through the subject evaporator. During this period of time other evaporators or evaporator modules within the same system will continue to function in the refrigeration mode.
2. Description of the Prior Art
The most recent developments in the prior art are shown in U.S. Pat. No. 3,905,202 issued Sept. 16, 1975 in which an energy conserving refrigeration system is disclosed which is operable to defrost evaporator modules by the passage of hot gaseous refrigerant therethrough. That system includes valving operable to maintain reverse flow through defrosting evaporators by maintaining a pressure differential thereacross while at the same time maintaining a minimum receiver pressure sufficient to insure efficient operation of the expansion valves of all the evaporators and evaporator modules which are then currently operating in the refrigeration rather than defrosting mode.
In order to further increase the efficient operation of that system, the present invention includes a means for decreasing the hot gas defrosting cycle time. In this manner defrost can be accomplished in a shorter period of time and all evaporators within the entire refrigeration system will be operating in the refrigeration mode for a greater percentage of total operation time than is possible during the operation of the original system as disclosed in the above patent.